The present invention related generally to cloth inspection machines and more specifically to a method of modifying cloth inspection machines to insure constant linear cloth speed.
Cloth inspection machines have ranged from the simple structure of U.S. Pat. Nos. 2,936,506 and 3,942,735 with no speed control to the speed control structure of U.S. Pat. Nos. 2,470,575 and 3,927,844. In U.S. Pat. No. 2,470,575 to Norton a mechanical lever detects the diameter of the material on the roll and provides adjustment of the mechanical speed changing device interconnecting the drive motor and the take-up reel. U.S. Pat. No. 3,927,844 to Bond et al. also includes a lever which is responsive to the diameter of a material being let off and adjusts a potentiometer which varies the speed of the motor. Without any speed control, the linear speed of the cloth could vary between 10 yards per minute at the beginning to 45 yards per minute at the end of the roll.
Both of the automatic motor speed changing inspection station devices by using a material rolled diameter measurement provides a crude speed adjustment. The linear speed of the material is kept certain limits which could not be considered substantially constant. Similarly, there are many applications wherein it is undesirable to have a roller or any other device in contact with the material. Thus it would be impossible to mechanically monitor the diameter of the roll. Similarly, the mechanical speed changing device of the Norton patent is very hard on the drive belts and consequently continuously needs replacement.
A typical cloth and inspection machine used throughout the industry is illustrated in FIGS. 1 and 2 as a Measurematic available from Cutting Room Appliances, New York, N.Y. The machine includes manual controls at the right side of the machine including a two-speed transmission for forward, reverse, and neutral as well as two speeds and a variable speed pulley and belt transmission controlled by a foot pedal to further vary the speed between the two speeds of the transmission. As with the Norton patent, the variable ratio pulleys and belt drive system are undesirable since they destroy a lot of belts. Also, the transmission slips with usage. Another limitation of this machine is that by placing the controls to one side of the inspection machine, the operators will position themselves close to the controls and will not detect flaws in the material for large width cloths.
As is well known, the speed of the inspection machine varies with the diameter of the material on the take-up reel. These machines require the operator to change the speed using the transmission as well as the variable speed changing foot pedal. Operators are generally lazy and will ignore the foot pedal speed change. Therefore, they will run it at substantially higher speeds than necessary which increases the error rate of detecting flaws.
Thus, there is a need in the industry for a cloth inspection station where the linear speed of the cloth is automatically controlled. Also, because of the large investment of various companies in cloth inspection machines, it would be a great advantage to have a method for modifying the existing manually operated speed change control to automatic control at a reasonable price.